Text entry is one of the vital issues for smart phones as well as for other compact hand held devices.
Many methods have been suggested in recent years. Among the most popular ones are methods that reduce the number of keys by grouping several letters together on a single key and use a prediction or disambiguating system to generate the desired text. Since fewer keys are needed, smaller keypad size or larger key size is obtainable. Less finger movements are needed hence typing speed is potentially increased. However, if the user desires to write a word that is not in the device's dictionary database, or if more than one valid word exists for a sequence of letter entries, a considerable degradation in typing speed and comfort occurs.
In U.S. Pat. No. 5,818,437 entitled “reduced keyboard disambiguating computer”, Grover, et al., a 3 by 4 numeric keypad is presented where each key is associated with 3 or 4 letters. In U.S. Pat. No. 5,847,697 entitled “Single-handed keyboard having keys with multiple characters and character ambiguity resolution logic”, Sugimoto, a half size QWERTY keyboard, with two letters associated to most of the keys, is presented. Similar arrangements and various types of keys arrangements and text prediction or disambiguation processing exists in prior art.
Ways to present the word list to the user and receiving the user selection of the desired word, including word completion, are available in prior art too.
None of the prior art combines predictive text entry methods with simple full keyboard text entry to provide unified text entry system.